Definition, classification, and routine diagnosis of urticaria: A consensus report

Urticaria is a well-known disease entity; however, with an increasing understanding of the molecular mechanisms involved in its pathogenesis, there is also growing evidence for a heterogeneity of urticaria. Currently it is sometimes difficult to compare divergent data reported by different centers researching urticaria due to a lack of precisely described patient populations. A consensus definition and classification of the disease and its subtypes, taking into account new developments, are therefore needed. In addition, this consensus report provides a guideline for diagnostic procedures in different subtypes of urticaria.